The former Air Chief, his cousins--Sanjeev alias Julie, Rajeev alias Docsa and Sandeep, European middlemen Carlo Gerosa, Christian Michel and Guido Haschke were among 13 individuals named in the FIR as accused, CBI sources said.
Shashi Tyagi is the first Chief of the Indian Air Force to be named in a corruption or criminal case by the CBI.
CBI alleged that during his tenure as Air Chief, Tyagi and "with his approval" the Air Force "conceded to reduce the service ceiling for VVIP helicopters from 6000 meters to 4500 meters as mandatory to which it was opposing vehemently on the grounds of security constraints and other related reasons," agency sources said.
It alleged that reduction of service ceiling--maximum height at which a helicopter can perform normally--allowed UK-based AgustaWestland to come into the fray as, otherwise, its helicopters were not even qualified for submission of bids.
Under the cover of these contracts, Haschke allegedly sent Euro 1.26 lakh and two lakh to Tyagi brothers.
"Besides these two remittances, Tyagi brothers also received some unquantified sum of money from the middlemen (Haschke and Gerosa). The inflow of remittances to Tyagi brothers and softening of IAF's stand on service ceiling of the helicopter closely match in terms of time," the FIR said.